This invention relates to a textile processing machine such as a drawing frame, a carding machine or the like which utilizes pneumatic pressure and which has at least one sliver guiding element such as a sliver trumpet through which the sliver runs and which is supplied with pressurized air.
In known drawing frames whose upper drawing rolls are loaded pneumatically, a central pneumatic conduit for the drawing frames is provided. From the central pneumatic conduit several branch conduits lead to the individual drawing frames. The pressure in the central pneumatic conduit and in the branch conduits is high (approximately 6-8 bar); for loading the upper rolls high pressure is required. The quantity of the pressurized air, however, is small because it is consumed only during the loading of the upper rolls. In contrast, the pressurized air which is supplied to the sliver trumpet has a low pressure of, approximately, 0.4 bar, and the quantity of air consumed by the sliver trumpet is large because a continuous supply of the air stream is needed. Conventionally, in order to generate the low pressure for the pressurized air stream intended for the sliver trumpet, in each branch conduit a pressure reducing valve is inserted. This arrangement is disadvantageous in that the generation of a large quantity of pressurized air of low pressure for the sliver trumpet involves a high energy input, resulting in a low efficiency of energy utilization.